/*******************************************************************************************
 * Copyright (c) 2006-2009 Alex Robson, Rob Simmons, Craig Israel, and Rachel Twyford
 *
 * Use of this software in any form requires that you have both 
 * read and agreed to the following terms:
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the "Software"), 
 * to deal in the Software without restriction, including without limitation 
 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions: 
 *
 * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 * Redistributions in binary form must reproduce the above copyright notice, 
 * this list of conditions and the following disclaimer in the 
 * documentation and/or other materials provided with the distribution.
 * Neither the name of Nvigorate nor the names of its contributors may 
 * be used to endorse or promote products derived from this software without 
 * specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
 * DISCLAIMED. IN NO EVENT SHALL ANY CONTRIBUTOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 * ****************************************************************************************/

using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using Nvigorate.Extensions;

namespace Nvigorate.Relational.Provider
{
    public class StatefulCollection<T> : Collection<T>, IStatefulList<T>
    {
        #region Fields

        protected List<T> _insertedSet;

        protected List<T> _deletedSet;

        #endregion

        #region Properties

        public List<T> InsertedSet
        {
            get
            {
                if (_insertedSet == null)
                    _insertedSet = new List<T>();
                return _insertedSet;
            }
            set { _insertedSet = value; }
        }

        public List<T> DeletedSet
        {
            get
            {
                if (_deletedSet == null)
                    _deletedSet = new List<T>();
                return _deletedSet;
            }
            set { _deletedSet = value; }
        }

        #endregion
        
        #region Constructors

        public StatefulCollection()
        {
        }

        public StatefulCollection(IEnumerable<T> source) : base()
        {
            source.ForEach(Add);
            _insertedSet.Clear();
        }

        #endregion

        #region Public Methods

        public object[] GetRemovedRelatives()
        {
            return _deletedSet.Cast<object>().ToArray();
        }

        public object[] GetAddedRelatives()
        {
            return _insertedSet.Cast<object>().ToArray();
        }

        public void ResetState()
        {
            InsertedSet.Clear();
            DeletedSet.Clear();
        }

        #endregion
        
        #region Protected Overrides

        protected override void ClearItems()
        {
            InsertedSet.Clear();
            DeletedSet.AddRange(this.Except(DeletedSet));
            base.ClearItems();
        }

        protected override void InsertItem(int index, T item)
        {
            InsertedSet.Add(item);
            DeletedSet.Remove(item);
            base.InsertItem(index, item);
        }

        protected override void RemoveItem(int index)
        {
            var item = base[index];
            base.RemoveItem(index);
            InsertedSet.Remove(item);
            DeletedSet.Add(item);
        }

        protected override void SetItem(int index, T item)
        {
            InsertedSet.Add(item);
            DeletedSet.Remove(item);
            base.SetItem(index, item);
        }

        #endregion

    }
}